Reinforced expansible tube



July 7, 1959 v BO DW H 2,893,431

REINFORCED EXPANSIBLEI TUBE Filed Nov. 24, 1954 4 She'ets-Sheet l H 2022 I8 W M/ 23 i;l I4 30 32 3| M Wm" 26 FIG.]SZ

um um K11 HIHII' IIL HIM 25 Ill- INVENTOR. HOEL L.. BOWDITCH AGENT July7, 1959 H. L. BOWDITCH 2,393,431

REINFORCED EXPANSIBLE TUBE Filed Nov. 24, 1954 4 Sheets-Sheet 2INVENTOR. l5 I6 HOEL L. BOWDITCH BY F AWE H @Etk AGENT July 7, 1959 H.BOWDITCH REINFORCED EXPANSIBLE TUBE 4 Sheets-Sheet 5 Filed Nov. 24. 1954INVENTOR. HOEL L. BOWDITCH OUT y man/CA AGENT y 7, 1959 H. BOWDITCH2,893,431

REINFORCED EXPANSIBLE TUBE Filed NOV; 24, 1954 4 Sheets-Sheet 4' ll mumm:

( By HOEL L. BOWDITCH IMJMAACL Y AG QNT United States Patent Ofice I2,893,431 Patented July 7, 1959 2 ,893, 81 REINFORCED EXPANSIB LE TUBE'Bowditch, Foxhoro, Mass assignor to The Fox- I new Company, Foxb'oro',"Massa corporation of Massachusetts 1 Application Nb tmber 24,19s4;.sens1No. 470,936

2 Claims." (0. 131-493 This invention relates to reinforced convolutedtubular .devices which areexpansiblelengthwise, such asbellowslike-structures with reinforcing means therefor.

Suchdevices areuseful, for example, as-fluid pressure sealing. units formovable: shafts, as flexible conduits, pressure sensing-elements, \valvemotors, and the like. It is' important forsuch 'devices tosbe veryflexible so that they can be-readily moved or adjusted according to theoperational movement or adjustment required of them, and for this reasonitisusually desirable 'toform the devicefrom relatively thin,v flexiblemetal. It is also important for such-devices tube-strong enough vtowithstand the operational pressures and 'movements to be appliedthereto.According Ito the concept of the present invention, it is; further,important for such devices. to have relatively uniform,-linearityapproachingmovement and strength characteristics with respectto operational pressures as applied-thereto in various stages ofmovement or adjustmentthereof. Thus the output movement of such adevice, according to this invention; closely approaches linearity withrespect to operational pressures applied thereto; for the purposes ofindication, recording, .or control; Further, the strength andflexibility characteristics of the unreinforced portions of the deviceaccordingv to thisin-vention areandremain essentially uniform undervariations of applied pressure and adjustment.

Thepresent invention provides, therefore, a reinfo'rced-expansible tubeunit which-has highstrength under fluid 'pressure and with respectto thetube material, condition, and thickness dimension, and which is providedwith "such form-andarrangement as to result inessentially linearmovement response to applied pressure, and in such uniform-elongation orbending upon readjustment as-to avoid concentrated or spot areas ofstress.

Thepre'sent-invention accordingly provides a reinforced 'expansible tubeunit" which is particularly useful in applications involving highfluidpressures, for example,

pressures of the'order of up to 40,000 p.s.i., although there is nospecific limit to the possible pressure range, since it depends in parton material, material condition,

. and dimensions.

It is therefore-an object of this invention to provide anew and improvedreinforced expansible tube.

:It is a further object to provide a newand improved high: pressurebellowsstructure.

Other objects and advantages of this invention will be- 2. device(Figure I) as an illustration of the cross-section form of the device;

Figure V1 is an enlarged showing of a cross-section slice fragment ofthe device according to Figure V, and is an illustration of a tubeformed in triple lamination as produced by initially providingacylindrical tube formed of three closely fitting telescoping sleeves;

Figure VII is a flexible coupling application showing of the structureof Figure I;

Figure VIII. is a valve stem seal application showing of the structureof Figure I;

Figure IX is an illustration of a device according to this inventionwithan internalshaft in longitudinal sliding fit within theconvolutionsthereof;

Figure. X is a fragmentary illustration of a further alternatestructure. in longitudinally central cross-section, wherein. thereinforcing ring, units are provided with dished guide andspringlOadihgdiscs;

Figure X1 is a plan view ofone of the dished disc rejinforcingring.units asused. in the structure of Figure X;

Figure XII- is an. edge View of the ring unit of Figure XI; s

Figure. XIII is awalve motor. applicationshowing of thestructure ofFigure I; and

Figure XIV is a pressure sensing showing, of. the structure of Figure I.

As amatter of convenience in the following description devices embodyingthis invention will be referred to hereinafter in the-specification asbellows units, in view of the bellowselike sidewall convolutions commonto the various. embodimentsof this invention as disclosed herein. I

Figure I presents a bellows unit 10 as an illustrative embodiment ofthis invention wherein ametal tube 11 is provided with annular.transverse convolutions 12. Between and defined by the. convolutions 12,annular valleys 13 are provided, with'reinforcing ring units or bodies14 mounted in the. valleys 13. Mounting, flanges- 15 and 16 areintegrally secured to the tube, one at each end thereof. The flanges15"and 16 are used to mount the bellows unit 10 on the particularassembly to which the bellows unit is to be. applied. Such arrangementsare shown in Figures VII, VIII, XIII and XIV. Figure II. is a planviewof'fiange 15. These flanges areshown as heavy discs such as may be usedin high pressure applications. Bolt holes 17 are provided in the flanges15,.16, for use in mounting the bellows unit, and the flanges areprovided With central, cylindrical openings 15, 16' through which thecylindrical ends of the tube element application .11 are extended, intight fitting integral mounting relation therewith. The flanges 1'5, 16are further provided with annular outer end bosses 18 and. 19 in.laterally flaring continuationof the flange central openings 15 and 16'.The tube 11 is similarly flared within the flange bosses 18 and 19 andthe outer ends of the tube and the flange bosses are welded together. inannular joining seals as at 20 and 21.'

The outer end faces of the flanges 15 and 16 are provided with annularstep abutments 22, 23 and 24, 25' as means for aiding the fitting andsealing of the flanges to suitably cooperating portions of the membersto which the bellows unit 10 is securedin its various applications. Theinner end faces of the flanges'I5-and16are provided with annularabutments 26 and 27 which are curved? in cross-section to engage andmatch aiportionof the:curva ture of the first of the tube convolutions12 at each end of the tube 11. Further, the inner end-.faces of'theflanges 15 and16provided with annularchannels-28nd 29 =whieh are curvedand relievedin-cross-section to provide expansion room for the tubeconvolutions 12,. lengthwise of the tube 11. As may be notedhereinafter, this flange inner face arrangement is simply a continuationof the greatest dimension, the

arrangements provided by each of the convolutions 12 by the reinforcingring units 14 which are adjacent thereto. Thus the flanges 15 and 16abut on portions of the first of the convolutions 12 -at,theirrespective ends of thetube11. In

As shown in Figures I, III, IV, the annular reinforcing ring units 14are formed with inner annular rings 30 and outer annular rings 31, andthese rings are joined by an annular, narrow neck portion 32. Withreference to dimension in the lengthwise direction of the tube 11 andthe bellows unit 10, this dimension being the thickness dimension of thering units 14; the outer ring has the inner ring has a lesser dimension,and the narrow neck has the least dimension. The ring ,units 14 aremounted on the tube 11 with the inner rings 30 bottomed in theconvolution valleys 13. The convolutions 12 are reentrant between theinner and outer rein- 11, as permitted by the narrowness of thereinforcing 'ring neck 32. Consequently the convolutions 12 radiallyoverlie portions of the reinforcing unit inner rings 30 and thus blockoff the reinforcing ring units 14 with respect to .movement radially outof the convolution valleys 13.

The configurations and dimensions of the tube convolushown generally inFigure I, are more clearly and acand VI.

The reinforcing unit inner ring 30 in transverse crosssection, i.e.centrally of the ring unit and lengthwise of the bellows unit asassembled thereon, is oval shaped,

.forcing unit rings 30 and 31 and lengthwise of the tube V curatelyshown in the enlarged showings of Figures V with the long dimensionlengthwise of the bellows unit,

and has end faces 33 curved on a radius 34. The valley (13) formationsof the tube 11 are in overall close engagement with the radially innerfaces and for the most part the cross-section end faces 33 .of thereinforcing unit inner rings 30.

Thus the bottom portions of the tube valleys 13 are r I rigid and takeno appreciable part in the flexing and elongation of the bellows unit.Further, very substantial reinforcement of the bellows unit at thevalley areas is provided by the reinforcing ring units 14. This rein-'forcement is not only transversely of the bellows units, vbut is alsolengthwise thereof. Such lengthwise reinforcement is provided at thereinforcing unit inner rings 30, since portions of adjacent convolutionsare rigidly separated at a fixed distance by the reinforcing unit inner,ring 30 therebetween. Thus, the flexing and elongations of the bellowsunit 10 is accomplished by flexing of the unrestricted portions of theconvolutions 12. Further lengthwise reinforcement of the bellows unit 10is promal, at rest condition is illustrated in Figure I, with the outerrings 31 somewhat separated from each other lengthwise of the bellowsunit. However, endwise crush- ,ing or tilting forces on the bellows unitare limited in the effect they can have on the convolutions 12 by thefact that after a short movement of compression, the reinforcing unitrings 31 are seated on each other to form a rigid cylinder. Thereinforcing unit rings 31 are formed a with flat upper and lower facesas a means of facilitating .units 14, while Figure VI shows a laminatedtube 11" the same configuration may also be provided in a single'thickness tube 11 (Figure V).

The reinforcing ring units 14 are formed with clearances 14 whichprovide room, both transversely and lengthwise of the bellows unit, forthe convolutions 12 to be expanded without backing or external restraintas they areformed into a close approximation of ,a circuvided by thereinforcement unit outer rings 31. A norlar contour as indicated inFigure VI, radius 35. Fun ther, the clearances 14' provide room for theconvolution to be flexed without hindrance throughout the operatingrange of the bellows unit, while essentially maintaining a circularcontour, although the radius thereof may be slightly changed during suchflexing. Such forming of the convolution provides a circular contourunder tension and with an appreciable grain component, both in thedirection of operational stress, generally lengthwise of the tube 11, asindicated in Figure VI by the arrows 36. Thus the convolutions 12 areprovided with uniform dynamic strain, and have no undesirableconcentrations of stresses. The dynamic relation of the circular form ofthe convolutions 12 as on the radius 35, to the circular forms of thecurved ends 33 of the reinforcing unit inner rings 30 as on the radius34, may be considered as one circle tangentially rolling on anothercircle. Further, as seen in cross section, Figure VI, the convolutions12 are each made up of a circular portion 37 stemming from a curved wallrelatively narrow neck portion 38,

jvolution. Such portions may vary somewhat in dimension as the bellowsunit 10 is flexed, but the greater part of each flexure convolution isunhindered and unsupported by backing walls or the like, throughout theoperating range of the device. Thus a bellows unit is provided whichclosely approaches linearity in its movement in response to fluidpressure as applied thereto.

The Figure VI laminated tube 11" structure provides the advantages ofseparate tube walls that may move with respect to each other during theforming and operation of a device according to this invention. Such anarrangement can be an aid in avoiding undesirable stress arrangements orconcentrations in the tube. The Figure V and VI showings of thisinvention illustrate how the 13. This structural arrangement isindicative of the reentrant form of the convolutions 12, lengthwise ofthe bel- I lows, and with respect to the annular reinforcing units 14.

This device is provided with circular cross-section shapes in theconvolutions 12, as illustrated in Figures V and VI. The annularreinforcing unit clearances 14 are suflicient to permit this actionwithout any backing or support for these circular forms, even with thereinforcing ring units 14 held in close engagement with each other bythe crushing pressure as applied endwise of the bellows unit.Consequently the convolutions 12, are under tension, uniformly, and inthe direction of the circular cross-section form of the convolutions,Figure VI, arrows 36. Further, the grain form is appreciably in thedirection of these arrows 36. Therefore flexing action of the bellowsunit upon application of fluid pressure thereto closely approacheslinearity of response. With this arrangement it will be seen that eachof the convolutions 12 has a flexible portion which is a large part ofthe whole convolution with this flexible portion remaining flexible,unhindered and externally unsupported, as a whole, throughout theoperating range of the bellows device. Certain small dimensional changesmay occur, that is, the circular cross-section radius may changeslightly during the operation of the device; the circular cross-sectionof the convolution may roll somewhat on the reinforcing unit inner ring30; or there may be slight slippage between the neck portion of theconvolution and the inner ring 30. In any case the dimensional changesthus brought about in the flexible portion of the convolution arerelatively quite small, with no ible portion of the convolution 'oronthe linearity ofthe device. r

, Figure VII shows the bellows unit of FigureI in an application as aflexible coupling on a high pressure fluid flow pipe line. The bellowsunit 10 connects two pipes 56 and 57 to form a continuous conduittherewith. The bellows unit flanges 1 5 and 16 are secured to pipeflanges 58 and 59, and the bellows unit is pressure sealed to-the pipeflanges. With t is arrangement the pipes 56 and 57 may be substantiallyout of alignment and the bellows unit may be subject to bending, withoutestab lishing stress concentrations in the bellows unit 10. Thisdesirable condition is made possible by the form and construction of thebellows unit as described hereinbefore and involving its linearresponse, its uniform tension dynamically and statically, its graindisposition, and the circular cross-section configuration of the bellowsconstruction.

Figure VIII shows the bellows unit 10 of Figure I in an application as ahigh pressure seal. In order to control flow in a pipe line it isconventional to mount a valve stem for movement through a wall of acontrol chamber. Under high pressure conditions such arrangementspresent difiicult problems with respect to sealing off the valve stemwithout undesirably alfecting its movement. The bellows unit of thisinvention provides a ready and practical solution to this problem, asillustrated in Figure VIII. In this figure, at the bottom thereof, aninput passage 60 leads to a control chamber 61 through a valvingaperture 62 and an output passage 63 leads from the chamber 61. A valvestem 64 extends into the chamber 61 and is movable to open and close thevalving aperture 62. One end of the bellows unit 10 is secured andsealed to the fixed valve chamber housing and the other end is securedand sealed to the valve stem 64. In this showing the valve stem 64 ismovable by a conventional fluid pressure diaphragm motor 65. The valvestem 64 is shown in two parts, but it is integral and solid from themotor 65 through the bellows unit 10 to the valving aperture 62.

Figure IX is an illustration of how a valve stem, or a shaft for otherpurposes, may be arranged within a bellows unit according to thisinvention. Figure IX shows a shaft 66 in sliding fit bearing relationwith the inner walls of the bellows unit 10. This is, for example, apressure seal structure such as item 10, Figure VIII, wherein the FigureVIII shaft 64 is enlarged, as at 66, Figure IX, to engage the innerwalls 13 of the bellows unit. The valleys 13 may have cylindrical innerwalls of special bearing material if desired. This arrangement also thusprovides means for preventing undesirable tilting of the bellows unit.

Figures X, XI, and XII are illustrative of a further alternate structureof this invention. A part of this structure duplicates, to the limit ofits fragmentary showing, the structure of Figure V. Additionally,however, each of the reinforcing ring units 14" is provided with a pairof dished, annular resilient discs or rings 69 as radially outwardextensions of the main bodies of the reinforcing ring units. On eachreinforcing unit the dished discs are placed in convex face to convexface relation with respect to each other. Under normal conditions, withthe main bodies of the reinforcing ring units 14" in spaced relationwith each other, the lower disc of one ring unit is in peripheralengagement with the upper disc of the ring unit next therebeneath. Thisengagement is spring biased lengthwise of the bellows unit. Consequentlythis form of this invention is spring loaded in the direction ofelongation of the bellows unit, and the discs 69 provide another form ofprotection against bellows buckling or tilting.

Figure XIII shows the bellows unit 10 of Figure I in an application as afluid pressure motor. That is, the bellows unit here is substituted forthe Figure VIH diaphragm motor 65. In this Figure XIII structure, oneend flange (15) of the bellows unit is secured and sealed to' a fixedmounting member 70, with a fluid pressure input passage 71 thereinleading to the upper open end of the bellows unit. There'is no shaftwithin the bellows, and pressure applied therewithin produces responsivemovement of the lower end bellows flange 16. This lower end of thebellows is sealed off against a solid mounting disc 72, and the upperend of a valve stem 73 is secured to the under side of the mounting disc72. The valve stem 73 is extended to indicate its use in a valve blockfor opening and closing a fluid flow passage 74.

Figure XIV shows the bellows unit .10 of Figure I in an application as afluid pressure sensing element. Such an element may have its lower endflange 16 fixedly mounted on a fluid flow pipe line 75, with an opening(not shown) providing access to the interior of the bellows from thepipe line 75. The upper end flange 15 of the bellows unit 10 is sealedolf against a solid disc 76 and is movable in response to fluidpressures applied within the bellows unit 10. As an indication of anapplication of such movement, a mechanical connection 77 is shown asoperating an indicator 78, pivoted as at 79, with respect to a scale 80.

This invention, therefore, provides a new and improved reinforcedconvoluted tubular device, such as a bellowslike structure withreinforcing means therefor.

As many embodiments may be made of the above invention, and as changesmay be made in the embodiments set forth above Without departing fromthe scope of the invention, it is to be understood that all matterhereinbefore set forth or shown in the accompanying drawings is to beinterpreted as illustrative only and not in limiting sense.

I claim:

1. A reinforced bellows unit comprising a transversely convoluted tubeand annular transversely reinforcing ring bodies mounted on said tubebetween the convolutions thereof, said reinforcing ring bodies eachhaving an inner annular ring, an outer annular ring, and a relativelynarrow annular neck portion joining said rings, each of saidconvolutions extending between said annular rings of each adjacent ringbody at the said annular neck portion thereof, and outer, lengthwisereinforcing and spring loading dished rings mounted on said outer anularrings, each of said outer rings being provided with a pair of saiddished rings arranged convex face to convex face lengthwise of saidtube, and the outer rim of each disc being in spring biased engagementwith the outer rim of a disc on the next adjacent outer annular ring.

2. A flexible, reinforced bellows-like unit comprising an integraltransversely multiconvoluted tube and individual reinforcing ring bodiesmounted on said tube between the convolutions thereof, said reinforcingring bodies each having an inner anular ring as a base form thereof withsaid base lying deep in the valley of one of said convolutions, an outeranular ring as a top thereof with said top lying above the peaks of theadjacent convolutions of said tube, and a relatively narrow neck portionjoining said base and top to form a joining leg on a radius of saidconvoluted tube, each of said convolutions having a transverse crosssection of essentially circular form in a plane extending lengthwise ofsaid tube, which is substantially greater than a semi-circle and whichbulges lengthwise of said tube to lie, on radii of said tube, betweenportions of the bases of the adjacent rings and portions of the tops ofsaid adjacent rings, said rings providing, with each adjacent pair ofrings, an annular housing chamber for one of said convolutions with anoperating clearance for said one of said convolutions sufiicient toenable said convolution to maintain said circular cross sectionthroughout the operating range of expansion of said tube, and said topsbeing formed and arranged for abutment with their adjacent tops as alimit stop system to limit the possible lengthwise compression of saidconvoluted tube.

(References on following page) Fulton Dec. 27, 1910 Sundh ..-Ju1y 22,1919 Vuilleumier Nov. 30, 1920 Lawrence Oct. 6, 1931 Lord Dec. 8, 1931May May 24, 1932 Zllea et a1 Nov. 29, 1949 10 8 Candee Aug. 7, 1951Chyle Aug. 21, 1951 Zallea Mar. 17, 1953 Schindlex: et a1. July. 7, 1953ZaHea; Jan. 18, 1955 Fentress et a1. Apr. 26, 1955 Schindler et a1. Jan.17, 1956 FOREIGN PATENTS France Ju1y23, 1951

